Shares in Volkswagen soared as much as 20% to a record €288.79 (£228.51) yesterday amid expectations that Porsche would raise its stake in the German carmaker. The shares have risen 33% since Tuesday, when Porsche said it had raised its stake in VW to more than 35%, which it said gave it effective control over Europe's largest carmaker. Porsche has said it plans to boost its holding above 50%, giving it a simple majority.

The company was not available to comment on whether it was buying VW shares yesterday but analysts said the share price jump was a result of short sellers closing their positions.

Robert Heberger, an analyst at German broker Merck Finck, said it was "hardly anything to do with fundamentals, it is just a short squeeze".